This research examines how sales professionals use emotions in marketing exchanges to facilitate positive outcomes for their firms, themselves, and their customers. The authors conduct three field studies to examine the impact of emotional intelligence (EI) in marketing exchanges on sales performance and customer relationships. They find that EI is positively related to performance of real estate and insurance agents, even when controlling for the effects of domain-general EI, self-report EI, cognitive ability, and several control variables. Sales professionals with higher EI are not only superior revenue generators but also better at retaining customers. In addition, the authors demonstrate that EI interacts with key marketing exchange variables—customer orientation and manifest influence—to heighten performance such that high-EI salespeople more effectively employ customer-oriented selling and influence customer decisions. Finally, the results indicate a complementary relationship between EI and cognitive ability in that EI positively influences performance at higher levels of cognitive ability. These findings have implications for improving interactions between buyers and sellers and for employee selection and training.